PURPOSE: To provide an output control device for an AC generator wherein an overload is prevented from being given to an internal combustion engine by properly controlling generating action timing of the AC generator.

CONSTITUTION: A device comprises an AC generator 1 driven by an internal combustion engine to generate AC voltage, rectifier 2 for converting the generated AC voltage into DC voltage and a storage battery 3 charged by this converted DC voltage. Further, the device has a charge control circuit 4A for determining a control quantity of field current, supplied to a field coil 1b of the generator 1 from the storage battery, to also stop supplying the field current, when the control quantity is a predetermined value or less, based on a voltage deviation amount between charge voltage and preset target voltage of the storage battery 3.